The present invention relates to a control device for optical and acoustical signal devices, particularly for the direction indicators and the horn of vehicles.
It is known to control the optical direction signaling devices or turn signal indicators of a motor vehicle by means of a direction signal control unit which is an integral part of the steering assembly of the vehicle and to control the acoustic signaler or horn by means of a second unit which is mounted on the steering column, usually on the same end to which the steering wheel is mounted. There is also frequently mounted on the steering wheel a third device which is a combination anti-theft/ignition switch device.
The direction signal control unit comprises generally two annular elements co-axial with the steering column of the vehice and arranged to cooperate with one another. One of the annular elements is rigidly connected to the steering wheel or the steering control arm by means of a third element called a link and which is mounted within the steering column. The automatic return of the two annular elements on which the direction signal control lever is mounted is possible because of the connection to the link. Suitable electric contacts or connections are provided on the steering wheel and are connected to one another by the displacement of the element which supports the control lever and which is used to accomplish the operation of the direction indicators.
The location of three separate devices on the steering column of the vehicle gives rise to several disadvantages. The correct operation of the ignition/anti-theft devices and the direction indicator control devices, in particular, require perfect centering of those devices on the steering column. As the two devices are independent from one another and are mounted separately, the perfect centering of both devices involves considerable assembly difficulties.
The location of the direction signal control unit involves additional assembly difficulties and also requires, moreover, an accurate and expensive manufacturing of the steering column itself as the steering column must be able to contain the workings of the direction signal control unit and also insure that the annular elements are co-axial. Finally, in the event of a malfunction or a failure, especially of an electrical failure, it is necessary to disassemble the steering wheel and the horn control unit in order to access the direction signal control device so as to carry out the necessary repair operations. Furthermore, the presence of electrical cables extending from the three devices and all being located within the steering column may give rise to an undesirable electrical contact and often even to electrical short circuits.